In this article, you will find information about the relatively new ECPR procedure, which improves traditional cardiopulmonary resuscitation (CPR) methods, but may be challenging to implement broadly across the country.
Improving Survival Rates
More than 300,000 people die each year in the United States from out-of-hospital cardiac arrest, making it a leading cause of death. Improving access to cardiopulmonary resuscitation (CPR) and defibrillators (which use electric shocks to restore a person’s heartbeat) has helped increase survival rates somewhat, but about 90 percent of cases remain fatal. Recent studies have shown that combining traditional CPR with a process called ECMO (which helps deliver oxygen to the brain and other vital organs using a device similar to a heart-lung machine) can significantly enhance the chances of survival after cardiac arrest.
Successful Clinical Trials
In 2020, a randomized clinical trial of this approach, known as Extracorporeal Cardiopulmonary Resuscitation (ECPR), at the University of Minnesota showed that this method resulted in a survival rate of 43 percent, compared to 7 percent in standard care. The result was considered so successful that the National Institutes of Health ended the study early, deeming it unethical to withhold the treatment from qualified individuals.
Technical and Logistical Challenges
The trial in Minnesota focused on a subset of cardiac arrest cases that initially responded to defibrillation, but other studies suggest that ECPR may help in non-shockable cases as well. However, technical and logistical challenges may hinder the adoption of this procedure as a standard for out-of-hospital cardiac arrest outside of major academic hospitals.
ECPR Technology
The fundamental technology behind ECPR dates back to the 1950s when both CPR and the first heart-lung machines were developed. Although the ECMO process, where blood is removed from a person, oxygenated, and then pumped back into their body, has become simpler over time, it has primarily been used in operating rooms and pediatric intensive care units. That changed in 2009 when doctors in Asia began using ECMO to treat patients hospitalized due to H1N1 influenza, leading to more widespread use of the technology. The use of ECMO during the COVID pandemic increased interest in the approach.
Challenges in Implementing ECPR
However, treating cardiac arrest with ECMO can be costly – costing hospitals tens of thousands of dollars per patient – and poses technical challenges. The ECPR team at the University of Minnesota is considered one of the best in the world. Dimitri Yanopoulos, the director of the university’s Resuscitation Medicine Center, is a highly trained and experienced specialist, and the university hospital is fully equipped to handle ECPR patients and provide the long-term and complex care they often require post-procedure. “If you don’t give people the time to survive, you’ll get worse outcomes,” says Yanopoulos.
Challenges in Expanding ECPR
Other hospitals have failed to find a clear benefit from ECPR. A study published earlier this year by a group in the Netherlands found no significant difference in survival rates between patients who received ECPR after cardiac arrest and those who did not. However, none of the hospitals participating in the study had much experience with performing ECPR, and it took them much longer, on average, than the University of Minnesota Hospital to successfully complete the procedure – a critical factor given the time-sensitive nature of cardiac arrest.
Improvement
Survival Opportunities
One of the main reasons that cardiac arrest is fatal is that it occurs quickly. Unlike a heart attack, which can develop gradually over several hours, cardiac arrest happens suddenly and without warning. Within seconds, the heart stops beating and blood stops circulating, preventing oxygen from reaching the brain. Chest compressions can partially restore blood flow, but not completely. “CPR is not perfect. It circulates blood much less efficiently than the normal cycle,” says Joseph Tuna, an emergency specialist who performs ECPR at the University of Utah.
Implementing ECPR in the Future
In contrast, ECPR can fully restore blood flow to a person. However, it is considered an invasive procedure and more complex to perform. A specialist – usually a physician with specialized training – must insert large tubes into the patient’s femoral blood vessels while the patient is receiving chest compressions. The procedure can cause excessive bleeding, as patients often take anticoagulants to prevent blood clots, which can clog the ECMO device that oxygenates the blood. Meanwhile, time goes by, with the chances of survival decreasing by about 20 percent every 10 minutes.
Expanding ECPR
For many people experiencing cardiac arrest, ECPR is not even an option, as they live too far from the large hospital where ECPR could previously be performed. Experts have been working to change that. The Yanopoulos team in Minneapolis began using a vehicle equipped with an ECMO device to reach people in rural and suburban areas, as well as teams in some other cities. In 2019, a team at the University of New Mexico introduced an ambulance equipped with a hand-cranked ECMO device, making it easier and cheaper to set up. “I am really trying to make it as simple as possible,” says Jonathan Marinaro, an emergency medicine professor at the university who led the program.
The Future of ECPR
Ultimately, ECPR may become simple enough in the next ten years that non-doctors can perform it, which could vastly expand the use of the procedure. However, increasing the number of hospitals currently offering ECPR could also save many lives, because many out-of-hospital cardiac arrests – nearly 350,000 cases yearly in the United States – occur near healthcare facilities. According to a recent study, less than 2 percent of people in the U.S. who experience cardiac arrest are eligible for ECPR, based on their location and patient selection criteria. “The challenge is the variation in our healthcare system,” says Cindy Hsu, an emergency physician and critical care specialist at the University of Michigan, who co-authored the study.
Post-ECPR Challenges
Even hospitals with ECMO programs may not be ready to care for individuals who have experienced cardiac arrest after receiving ECPR. Complications, including internal bleeding and multiple organ failure, may require surgery and other interventions. Additionally, patients need to receive treatment for the underlying issues that led to their hearts stopping. Doctors want to ensure that patients have enough time to recover. However, there are also concerns that ECPR may leave people in an untenable state, for example, if they survive but are left with severe brain damage or cannot survive outside the hospital. “This is a problem with ECMO for sure, but it’s a problem with every new technology that provides life support,” says Stephen Latham, director of Yale University’s bioethics center.
ECPR
Not a Definitive Treatment
In the end, ECPR is not a definitive treatment for cardiac arrest. “It’s a life-saving process – delivering blood and giving the body time to recover, if it can,” says Yanopoulos. However, it may now be the best chance for survival for individuals whose lives would be lost without the procedure. “Some of these patients are very young, so we are extending their lives by several additional decades, and they can lead functional lives afterwards,” says Hsu.
Source: Erica Westly
Source: https://www.scientificamerican.com/article/ecpr-could-prevent-many-more-cardiac-arrest-deaths/
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